1. Field of the Invention
The present invention relates to an external light shielding film for a display apparatus, a method of manufacturing the same, and a filter for a display apparatus having the same, and more particularly, to an external light shielding film for a display apparatus, a method of manufacturing the same, and a filter for a display apparatus having the same, which can increase a contrast ratio in a bright room.
2. Description of Related Art
As modern society becomes more information oriented, technology of parts and devices related to image displays is remarkably advancing, and these parts and devices are becoming widespread. Display apparatuses utilizing parts and devices related to photoelectronics are becoming significantly widespread and used for television apparatuses, monitor apparatuses of personal computers, and the like. Also, display apparatuses are becoming both larger and thinner.
Plasma display panel (PDP) apparatuses are generally gaining popularity as next-generation display apparatuses to simultaneously satisfy a trend of becoming larger, and of becoming thinner, when compared with cathode-ray tubes (CRTs) representing existing display apparatuses.
The PDP apparatus generates a gas discharge between electrodes by a direct current (DC) voltage or an alternating current (AC) voltage which are supplied to the electrodes. Here, ultraviolet light is generated. Then, a phosphor is exited by ultraviolet light, thereby emitting light. However, the PDP apparatus has a defect in that an amount of emitted electromagnetic (EM) radiation and near infrared (NIR) radiation with respect to a driving characteristic is great, surface reflectivity of the phosphor is great, and color purity due to orange light emitted from helium (He), or xenon (Xe) used as a sealing gas is lower than the CRT. Accordingly, EM radiation and NI radiation generated in the PDP apparatus may have harmful effects on human bodies, and cause sensitive equipment such as wireless telephones, remote controls, and the like, to malfunction.
Therefore, in order to use the PDP apparatus, it is required to prevent emission of EM radiation and NI radiation emitted from the PDP apparatus from increasing to more than a predetermined level. PDP filters having functions such as an EM radiation-shielding function, an NI radiation-shielding function, a surface antiglare function, enhancement of color purity, and the like, are used for EM radiation-shielding and NI radiation-shielding while simultaneously reducing reflected light, and enhancing color purity. Since the PDP filter is equipped in a front unit of the panel assembly, transparency is required to simultaneously emit light and perform shielding functions.
External light may enter the panel assembly passing through the PDP filter in a condition where an outer surface is bright, that is, in a bright room condition with the PDP apparatus according to the conventional art. Accordingly, an overlapping between incident light generated in the discharge space of the panel assembly, and the external light entered passing through the PDP filter from the outer surface occurs. Accordingly, a contrast ratio decreases in the bright room condition, and therefore screen display capacity of the PDP apparatus is deteriorated. In order to overcome the above-mentioned problems, a PDP filter including an external light shielding film which is filled with a light absorbing substance so as to absorb external light has been disclosed.
In the case where external light is absorbed by an external light shielding film filled with a light absorbing substance, when the external light shielding film is filled with a large quantity of the light absorbing substance, problems of the contrast ratio becoming decreased in the bright room condition, and the screen display capacity becoming deteriorated may be solved. However, since the external light shielding film is not completely filled with the light absorbing substance in a general filling process, a filling defect caused by the light absorbing substance being exposed as is on an outer surface of the display apparatus, thereby generating a line shaped defect on the display.
Also, a visible ray transmittance and a viewing angle of the display apparatus are reduced due to the above-mentioned problems.